Spacing sticks are placed between tiers of lumber in a lumber package for effective kiln or air drying. In the prior art, spacing stick placing devices would hang-up or misdeliver spacing sticks so that consistent and accurate delivery of spacing sticks to desired pre-determined positions upon each tier of lumber could not consistently be achieved. Consequently it is an object of the present invention to provide a device for consistent and accurate delivery of spacing sticks to desired pre-determined positions upon consecutive tiers of lumber in a lumber stack. It is a further object to provide such a device which may be retro-fitted to existing lumber stacking apparatus, which stick placing device will increase the speed of stick delivery over that currently provided in the prior art, the device capable of handling and placing a variety of spacing stick widths and thicknesses.
In the prior art, applicant is aware of U.S. Pat. No. 3,823,834 which issued to Rysti on Jul. 16, 1974 for "Method and Device for Performing the Insertion of Piling Strips in Timber Packages". Rysti discloses using an opposed pair of J-hook spacing stick conveyors for translating spacing sticks from a spacing stick allocator over a stack of lumber, each spacing stick carried in an opposed pair of J-hooks. A vertically movable frame having longitudinally displaceable spacing stick carrying hooks depending therefrom may be elevated so as to substantially horizontally align the longitudinally translatable hooks with the opposed pair of J-hooks carrying a spacing stick. The longitudinally translatable hooks may then be longitudinally translated so as to transfer the spacing stick from the opposed pair of J-hooks to the longitudinally translatable hooks. For this operation, the J-hook spacing stick conveyor is stationary. It is also taught that in order to accomplish this transfer of the spacing stick, the J-hook spacing stick conveyor may be moved in a reverse direction.
With the spacing stick transferred to the longitudinally translatable hooks, the vertically moveable frame may be lowered so as to bring the longitudinally translatable hooks carrying the spacing sticks into proximity with the top-most tier of lumber in the lumber stack. The longitudinally translatable hooks are then translated in a reverse direction to their first direction of longitudinal translation thereby depositing the spacing sticks onto the top-most tier of lumber by the action of stops depending from the vertically movable frame. The stops do not move when the longitudinally translatable hooks are translated and thus push the spacing sticks from the hooks.
The present invention improves on the Rysti vertically moveable frame stick-placing device by removing the requirement as taught by Rysti that the J-hook spacing stick conveyor be stationary when the spacing sticks are transferred to spacing stick carrying hooks on the vertically moveable frame. Consequently in the present invention speed of delivery of spacing sticks is increased in that the J-hook spacing-stick conveyor need not be brought to a halt and then re-started for every cycle of the stick placing device.
Applicant has found that if stick placing devices, of which the Rysti device is one, are used where it is desired to operate the spacing-stick conveyor at higher speeds, the spacing-stick being removed by the vertically moveable frame interferes with the next advancing J-hook on the conveyor. Typically the vertically moveable frame cannot be actuated quickly enough to remove the spacing-stick from the opposed pair of J-hooks carrying the spacing-stick and lower the spacing-stick out of the way of the next advancing opposed pair of J-hooks so that the next advancing opposed pair of J-hooks come into contact with the spacing-stick.
Consequently it is an object of the present invention to provide a vertically moveable frame stick-placing device having a second longitudinally slidable spacing-stick removing frame which can be longitudinally translated relative to the vertically moveable frame so that spacing-sticks can be removed from a moving spacing-stick conveyor and in particular from a relatively high-speed continuously moving spacing-stick conveyor. It is a further object to provide a spacing-stick placer that can place end spacing-sticks flush with the first edge and the last edge of a lumber stack in the direction of travel of spacing-sticks on the conveyor.